<!-- 参考至 https://codepen.io/andymerskin/pen/XNMWvQ -->
<template>
  <div class="parallax-depth">
    <!-- <h1 class="title">Hover over the cards</h1> -->
    <div class="container">
      <card
        v-for="(item, index) in data"
        :key="index"
        :data-image="item.sourceUrl"
        @click="clickItem(item)"
      >
        <template v-slot:header>
          <h1>{{item.title}}</h1>
        </template>
        <template v-slot:content>
          <p>{{item.description}}</p>
        </template>
      </card>
    </div>
  </div>
</template>

<script>
const Card = {
  template: `
    <div class="card-wrap"
      @mousemove="handleMouseMove"
      @mouseenter="handleMouseEnter"
      @mouseleave="handleMouseLeave"
      ref="card">
      <div class="card"
        @click="clickItem(item)"
        :style="cardStyle">
        <div class="card-bg" :style="[cardBgTransform, cardBgImage]"></div>
        <div class="card-info">
          <slot name="header"></slot>
          <slot name="content"></slot>
        </div>
      </div>
    </div>`,
  mounted() {
    this.width = this.$refs.card.offsetWidth;
    this.height = this.$refs.card.offsetHeight;
  },
  props: ['dataImage'],
  data: () => ({
    width: 0,
    height: 0,
    mouseX: 0,
    mouseY: 0,
    mouseLeaveDelay: null
  }),
  computed: {
    mousePX() {
      return this.mouseX / this.width;
    },
    mousePY() {
      return this.mouseY / this.height;
    },
    cardStyle() {
      const rX = this.mousePX * 30;
      const rY = this.mousePY * -30;
      return {
        transform: `rotateY(${rX}deg) rotateX(${rY}deg)`
      };
    },
    cardBgTransform() {
      const tX = this.mousePX * -40;
      const tY = this.mousePY * -40;
      return {
        transform: `translateX(${tX}px) translateY(${tY}px)`
      }
    },
    cardBgImage() {
      return {
        backgroundImage: `url(${this.dataImage})`
      }
    }
  },
  methods: {
    handleMouseMove(e) {
      this.mouseX = e.pageX - this.$refs.card.offsetLeft - this.width/2;
      this.mouseY = e.pageY - this.$refs.card.offsetTop - this.height/2;
    },
    handleMouseEnter() {
      clearTimeout(this.mouseLeaveDelay);
    },
    handleMouseLeave() {
      this.mouseLeaveDelay = setTimeout(()=>{
        this.mouseX = 0;
        this.mouseY = 0;
      }, 1000);
    },
    clickItem(item){
      this.$emit("clickItem",item)
    }
  }
}
export default {
  components:{
    "card":Card
  },
  props:{
    data:{
      type:Array,
      default:()=>[]
    }
  },
  methods:{
    clickItem(item){
      this.$emit("clickItem",item)
    }
  }
}
</script>

<style lang="scss">
$hoverEasing: cubic-bezier(0.23, 1, 0.32, 1);
$returnEasing: cubic-bezier(0.445, 0.05, 0.55, 0.95);

.parallax-depth {
  margin: 40px 0;
  font-family: "Raleway";
  font-size: 14px;
  font-weight: 500;
  // background-color: #bcaaa4;
  -webkit-font-smoothing: antialiased;
  height: 90vh;
}

.title {
  font-family: "Raleway";
  font-size: 24px;
  font-weight: 700;
  color: #5d4037;
  text-align: center;
}

p {
  line-height: 1.5em;
}

h1 + p,
p + p {
  margin-top: 10px;
}

.container {
  // padding: 40px 80px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
}

.card-wrap {
  margin: 10px;
  transform: perspective(800px);
  transform-style: preserve-3d;
  cursor: pointer;
  // background-color: #fff;

  &:hover {
    .card-info {
      transform: translateY(0);
    }
    .card-info p {
      opacity: 1;
    }
    .card-info,
    .card-info p {
      transition: 0.6s $hoverEasing;
    }
    .card-info:after {
      transition: 5s $hoverEasing;
      opacity: 1;
      transform: translateY(0);
    }
    .card-bg {
      transition: 0.6s $hoverEasing, opacity 5s $hoverEasing;
      opacity: 0.8;
    }
    .card {
      transition: 0.6s $hoverEasing, box-shadow 2s $hoverEasing;
      box-shadow: rgba(white, 0.2) 0 0 40px 5px, rgba(white, 1) 0 0 0 1px,
        rgba(black, 0.66) 0 30px 60px 0, inset #333 0 0 0 5px,
        inset white 0 0 0 6px;
    }
  }
}

.card {
  position: relative;
  flex: 0 0 240px;
  // width: 240px;
  // height: 320px;
  width: 30vh;
  height: 40vh;
  background-color: #333;
  overflow: hidden;
  border-radius: 10px;
  box-shadow: rgba(black, 0.66) 0 30px 60px 0, inset #333 0 0 0 5px,
    inset rgba(white, 0.5) 0 0 0 6px;
  transition: 1s $returnEasing;
}

.card-bg {
  opacity: 0.5;
  position: absolute;
  top: -20px;
  left: -20px;
  width: 100%;
  height: 100%;
  padding: 20px;
  background-repeat: no-repeat;
  background-position: center;
  background-size: cover;
  transition: 1s $returnEasing, opacity 5s 1s $returnEasing;
  pointer-events: none;
}

.card-info {
  padding: 20px;
  position: absolute;
  bottom: 0;
  color: #fff;
  transform: translateY(40%);
  transition: 0.6s 1.6s cubic-bezier(0.215, 0.61, 0.355, 1);

  p {
    opacity: 0;
    text-shadow: rgba(black, 1) 0 2px 3px;
    transition: 0.6s 1.6s cubic-bezier(0.215, 0.61, 0.355, 1);
  }

  * {
    position: relative;
    z-index: 1;
  }

  &:after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    z-index: 0;
    width: 100%;
    height: 100%;
    background-image: linear-gradient(
      to bottom,
      transparent 0%,
      rgba(#000, 0.6) 100%
    );
    background-blend-mode: overlay;
    opacity: 0;
    transform: translateY(100%);
    transition: 5s 1s $returnEasing;
  }
}

.card-info h1 {
  font-family: "Playfair Display";
  font-size: 36px;
  font-weight: 700;
  text-shadow: rgba(black, 0.5) 0 10px 10px;
}
</style>